The site is slow on a phone.
The homepage takes 4.8 seconds to show its main content on a typical phone. Two uncompressed images and a chat widget that loads first account for most of it.
Two thirds of your visitors are on a phone, and they apply at less than half the desktop rate. Many leave before the page finishes loading.
Resize and compress the images, load the chat widget after the page, and test again on a mid-range phone over a mobile network.